My environment is SharePoint 2010. I was working on some master page changes and accidently I opened default master from (C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\GLOBAL\default.master) in SharePoint designer for some reason it removes the "~/" from the path of following user controls

I opened my default master in notepad and corrected the path by adding the tilde and slash but still my master page is not loading properly and i get the "File Not Found error". In view source the error is "/_catalogs/masterpage/_controltemplates/Welcome.ascx does not exist"

Even I tried to reset the master page back to site definition but it didn't help either.
–
V.BFeb 24 '12 at 5:25

can you configure the web.config to display the detailed error? Make - <CustomErrors Mode="Off">, CallStack="true" and <compilation debug="true" /> and then refresh the site.
–
Deepu NairFeb 24 '12 at 8:29

yes i have these settings.it shows me error that welcome.acsx doesn't exist though its present physically.
–
V.BFeb 24 '12 at 16:43

you wouldn't by any chance have the publishing feature enabled and be able to restore an earlier version? Also you mention you're working on a 2010 install, I would have thought that you would have been working with v4.master
–
pigeonFeb 24 '12 at 23:04

Well I think default.master should be the culprit as all this started after opening it in SPD
–
V.BFeb 25 '12 at 7:36